ACHIEVING AND MAINTAINING COMPLIANCE WITH THE KETOGENIC DIET

The ketogenic diet, a treatment for intractable epilepsy, is rarely initiated because it requires strict compliance with a diet that is perceived to be unpalatable. In a case study of a 15-year-old girl with uncontrolled epilepsy, we used a stimulus-choice procedure to assess relative preferences of 33 foods from the diet and to develop two treatments based on Premack's principle. The results of a multielement analysis showed that both treatments increased dietary compliance. Compliance was maintained with generalization of treatment across settings, and was associated with a 40% reduction in seizures.     

The values of science: Empiricism from a feminist perspective

This essay delineates the contributions of feminist critiques of science to contemporary reconstructions of empiricism. I argue that three central tenets arise from feminist attention to the dynamics of gender and oppression in the theories and methods of science: 1) a rejection of the science/politics dichotomy; 2) an acknowledgement of the epistemic import of subjective components of knowledge; and 3) a reconfiguration of the subject of knowledge. These three tenets are illustrated and supported through examples from the history of science.     

Suicide attempts in twins whose co-twins' deaths were non-suicides

Familial similarity for suicidal behavior has been interpreted by psychosocially oriented researchers as reflecting extreme grief following loss. This view would anticipate a higher frequency of attempted suicide among bereaved MZ than DZ twins (regardless of cause of death), given their generally increased social closeness. Alternatively, support for a genetic influence on suicidal behavior has been provided by findings of greater concordance among monozygotic (MZ) than dizygotic (DZ) twins, and among biological than adoptive relatives. This approach predicts that the occurrence of suicidal attempts among bereaved MZ and DZ twins whose co-twins deaths were non-suicides should not differ and should be low in frequency, given an absence of predisposing genetic factors. Attempted suicide was compared in 166 MZ and 79 DZ twins whose co-twins' deaths were non-suicides. Suicidal attempts (during the first two months following the loss) were recalled by 3 MZ twins (1.8%) and by 3 DZ twins (3.7%), a difference that was not significant. The present study, together with previous twin and adoption studies, supports the view that concordance for suicide among family members reflects a common genetic predisposition to suicidal behavior.     

Challenges confronting cross-sex friendships: “Much ado about nothing?”

This research was an investigation into four challenges purported to confront cross-sex friends. One hundred and thirty eight individuals (females = 86, males = 52) completed two surveys designed to explore the extent to which the sexual, emotional bond, audience, and equality challenges were present in their cross-sex friendships. Over 98% of the participants were heterosexual, 99% were Caucasian, and approximately 5% were Hispanic. Data gathered from the first survey were analyzed using a three-way analysis of variance, with gender, type of friendship, and romantic status as the independent variables, and three of the four challenges as the dependent variables. The first survey also included open-ended questions designed to explore the nature and existence of the challenges. The second survey was in a diary format. Respondents kept a frequency count for three weeks of discussions they had with their cross-sex friend concerning the challenges, and thoughts that they had as individuals concerning those challenges. Results from both surveys indicate that though the challenges exist and have powerful effects on a small percentage of individuals in cross-sex friendships, for the majority of participants the challenges are not perceived as salient.     

THE TREATMENT OF COVERT SELF-INJURY THROUGH CONTINGENCIES ON RESPONSE PRODUCTS

Assessment and treatment of covert self-injurious behavior are complicated because it is difficult to quantify and apply differential consequences to covert responses. In this study, both tangible and social reinforcers were identified using reinforcer assessment methods. These reinforcers were then provided contingent upon the absence of tissue damage identified during physical examinations, resulting in near 100% success in physical assessment checks that was maintained over 10 months.     

The Impact of Procedural Justice on Opinions of Public Policy: Solid Waste Management as an Example1

This study assessed the applicability of Tyler and Lind's (1992) relational model of authority to the context of local government policies on solid waste management. Tests of the hypothesized relations proposed by Tyler and Lind, accomplished through structural equation modeling, revealed that our data supported the relations between the various constructs of the model. Perceptions of both process control and relational process were found to be positively related to procedural fairness judgments, while procedural fairness judgments were weakly related to evaluations of government entities. Contrary to our expectations, a similar structural equation model test of an extension of the Tyler and Lind model showed that the model constructs were unrelated to respondents' opinions of public policies. The results also indicated that respondents living in communities with different infrastructures and political climates differed slightly in their perceptions of procedural justice and related constructs, but did not differ in their endorsement of the various solid waste management policies.     

Changeover behavior and preference in concurrent schedules

Pigeons were trained on a multiple schedule of reinforcement in which separate concurrent schedules occurred in each of two components. Key pecking was reinforced with milo. During one component, a variable-interval 40-s schedule was concurrent with a variable-interval 20-s schedule; during the other component, a variable-interval 40-s schedule was concurrent with a variable-interval 80-s schedule. During probe tests, the stimuli correlated with the two variable-interval 40-s schedules were presented simultaneously to assess preference, measured by the relative response rates to the two stimuli. In Experiment 1, the concurrently available variable-interval 20-s schedule operated normally; that is, reinforcer availability was not signaled. Following this baseline training, relative response rate during the probes favored the variable-interval 40-s alternative that had been paired with the lower valued schedule (i.e., with the variable-interval 80-s schedule). In Experiment 2, a signal for reinforcer availability was added to the high-value alternative (i.e., to the variable-interval 20-s schedule), thus reducing the rate of key pecking maintained by that schedule but leaving the reinforcement rate unchanged. Following that baseline training, relative response rates during probes favored the variable-interval 40-s alternative that had been paired with the higher valued schedule. The reversal in the pattern of preference implies that the pattern of changeover behavior established during training, and not reinforcement rate, determined the preference patterns obtained on the probe tests.     

Many-Valued Logic and Event-Related Potentials

In previous experiments on event-related potentials (ERPs) during linguistic judgments, the subjects' decisions have been categorical (e.g., true vs false). In this experiment, more realistic variations in truth value and subject certainty were used. Thirty-eight naive undergraduates read a story about a fictional murder. ERPs were recorded as the subjects rated the strength of their beliefs about statements relating to suspects in the crime. Because no subject was sure which of the suspects was guilty of committing the crime, binary (true–false) category judgments were inappropriate. Three components of the ERP waveforms were affected by the experimental manipulations. An early positive component was largest to sentences concerning the suspect considered most likely to have committed the crime. A subsequent broad posterior positivity (LPC) also showed significant sentence-type differences, but it was larger to sentences considered probable—whether they were true or false—than to more ambiguous sentences. A third ERP component (N400) was negative at midline electrode sites and peaked at approximately 420 ms. Subjects' truth-value judgments had no effect on the N400. N400 was, however, affected by the subject's task. It was more negative when subjects made graded judgments about truth value than when they made binary true–false judgments. Overall, naturalistic judgments of sentence validity produced a variety of brain responses that reflected different aspects of linguistic decision making.     

Congruence of meaning between facial expressions of emotion and selected emotion terms

How similar are the meanings of facial expressions of emotion and the emotion terms frequently used to label them? In three studies, subjects made similarity judgments and emotion self-report ratings in response to six emotion categories represented in Ekman and Friesen's Pictures of Facial Affect, and their associated labels. Results were analyzed with respect to the constituent facial movements using the Facial Action Coding System, and using consensus analysis, multidimensional scaling, and inferential statistics. Shared interpretation of meaning was found between individuals and the group, with congruence between the meaning in facial expressions, labeling using basic emotion terms, and subjects' reported emotional responses. The data suggest that (1) the general labels used by Ekman and Friesen are appropriate but may not be optimal, (2) certain facial movements contribute more to the perception of emotion than do others, and (3) perception of emotion may be categorical rather than dimensional.     

Are research subjects adequately protected? A review and discussion of studies conducted by the Advisory Committee on Human Radiation Experiments

In light of information uncovered about human radiation experiments conducted during the Cold War, an important charge for the Advisory Committee on Human Radiation Experiments was to assess the current state of protections for human research subjects. This assessment was designed to enhance the Committee's ability to make informed recommendations for the improvement of future policies and practices for the protection of research subjects. The Committee's examination of current protections revealed great improvement over those from the past, yet some problems remain. Although the data collected by the Committee highlight specific areas in need of attention, the Committee's work should be viewed in part as the beginning of a series of ongoing assessments of the adequacy and effectiveness of the protections afforded to human subjects.